1,078 research outputs found
Design and Analysis of a Novel Split and Aggregated Transmission Control Protocol for Smart Metering Infrastructure
Utility companies (electricity, gas, and water suppliers), governments, and
researchers recognize an urgent need to deploy communication-based systems to
automate data collection from smart meters and sensors, known as Smart Metering
Infrastructure (SMI) or Automatic Meter Reading (AMR). A smart metering system
is envisaged to bring tremendous benefits to customers, utilities, and
governments. The advantages include reducing peak demand for energy, supporting
the time-of-use concept for billing, enabling customers to make informed
decisions, and performing effective load management, to name a few.
A key element in an SMI is communications between meters and utility servers.
However, the mass deployment of metering devices in the grid calls for studying
the scalability of communication protocols. SMI is characterized by the
deployment of a large number of small Internet Protocol (IP) devices sending
small packets at a low rate to a central server. Although the individual
devices generate data at a low rate, the collective traffic produced is
significant and is disruptive to network communication functionality. This
research work focuses on the scalability of the transport layer
functionalities. The TCP congestion control mechanism, in particular, would be
ineffective for the traffic of smart meters because a large volume of data
comes from a large number of individual sources. This situation makes the TCP
congestion control mechanism unable to lower the transmission rate even when
congestion occurs. The consequences are a high loss rate for metered data and
degraded throughput for competing traffic in the smart metering network.
To enhance the performance of TCP in a smart metering infrastructure (SMI), we
introduce a novel TCP-based scheme, called Split- and Aggregated-TCP (SA-TCP).
This scheme is based on the idea of upgrading intermediate devices in SMI
(known in the industry as regional collectors) to offer the service of
aggregating the TCP connections. An SA-TCP aggregator collects data packets
from the smart meters of its region over separate TCP connections; then it
reliably forwards the data over another TCP connection to the utility server.
The proposed split and aggregated scheme provides a better response to traffic
conditions and, most importantly, makes the TCP congestion control and flow
control mechanisms effective. Supported by extensive ns-2 simulations, we show
the effectiveness of the SA-TCP approach to mitigating the problems in terms of
the throughput and packet loss rate performance metrics.
A full mathematical model of SA-TCP is provided. The model is highly accurate
and flexible in predicting the behaviour of the two stages, separately and
combined, of the SA-TCP scheme in terms of throughput, packet loss rate and
end-to-end delay. Considering the two stages of the scheme, the modelling
approach uses Markovian models to represent smart meters in the first stage and
SA-TCP aggregators in the second. Then, the approach studies the interaction of
smart meters and SA-TCP aggregators with the network by means of standard
queuing models. The ns-2 simulations validate the math model results.
A comprehensive performance analysis of the SA-TCP scheme is performed. It
studies the impact of varying various parameters on the scheme, including the
impact of network link capacity, buffering capacity of those RCs that act as
SA-TCP aggregators, propagation delay between the meters and the utility
server, and finally, the number of SA-TCP aggregators. The performance results
show that adjusting those parameters makes it possible to further enhance
congestion control in SMI. Therefore, this thesis also formulates an
optimization model to achieve better TCP performance and ensures satisfactory
performance results, such as a minimal loss rate and acceptable end-to-end
delay. The optimization model also considers minimizing the SA-TCP scheme
deployment cost by balancing the number of SA-TCP aggregators and the link
bandwidth, while still satisfying performance requirements
Design and Analysis of a Novel Split and Aggregated Transmission Control Protocol for Smart Metering Infrastructure
Utility companies (electricity, gas, and water suppliers), governments, and
researchers recognize an urgent need to deploy communication-based systems to
automate data collection from smart meters and sensors, known as Smart Metering
Infrastructure (SMI) or Automatic Meter Reading (AMR). A smart metering system
is envisaged to bring tremendous benefits to customers, utilities, and
governments. The advantages include reducing peak demand for energy, supporting
the time-of-use concept for billing, enabling customers to make informed
decisions, and performing effective load management, to name a few.
A key element in an SMI is communications between meters and utility servers.
However, the mass deployment of metering devices in the grid calls for studying
the scalability of communication protocols. SMI is characterized by the
deployment of a large number of small Internet Protocol (IP) devices sending
small packets at a low rate to a central server. Although the individual
devices generate data at a low rate, the collective traffic produced is
significant and is disruptive to network communication functionality. This
research work focuses on the scalability of the transport layer
functionalities. The TCP congestion control mechanism, in particular, would be
ineffective for the traffic of smart meters because a large volume of data
comes from a large number of individual sources. This situation makes the TCP
congestion control mechanism unable to lower the transmission rate even when
congestion occurs. The consequences are a high loss rate for metered data and
degraded throughput for competing traffic in the smart metering network.
To enhance the performance of TCP in a smart metering infrastructure (SMI), we
introduce a novel TCP-based scheme, called Split- and Aggregated-TCP (SA-TCP).
This scheme is based on the idea of upgrading intermediate devices in SMI
(known in the industry as regional collectors) to offer the service of
aggregating the TCP connections. An SA-TCP aggregator collects data packets
from the smart meters of its region over separate TCP connections; then it
reliably forwards the data over another TCP connection to the utility server.
The proposed split and aggregated scheme provides a better response to traffic
conditions and, most importantly, makes the TCP congestion control and flow
control mechanisms effective. Supported by extensive ns-2 simulations, we show
the effectiveness of the SA-TCP approach to mitigating the problems in terms of
the throughput and packet loss rate performance metrics.
A full mathematical model of SA-TCP is provided. The model is highly accurate
and flexible in predicting the behaviour of the two stages, separately and
combined, of the SA-TCP scheme in terms of throughput, packet loss rate and
end-to-end delay. Considering the two stages of the scheme, the modelling
approach uses Markovian models to represent smart meters in the first stage and
SA-TCP aggregators in the second. Then, the approach studies the interaction of
smart meters and SA-TCP aggregators with the network by means of standard
queuing models. The ns-2 simulations validate the math model results.
A comprehensive performance analysis of the SA-TCP scheme is performed. It
studies the impact of varying various parameters on the scheme, including the
impact of network link capacity, buffering capacity of those RCs that act as
SA-TCP aggregators, propagation delay between the meters and the utility
server, and finally, the number of SA-TCP aggregators. The performance results
show that adjusting those parameters makes it possible to further enhance
congestion control in SMI. Therefore, this thesis also formulates an
optimization model to achieve better TCP performance and ensures satisfactory
performance results, such as a minimal loss rate and acceptable end-to-end
delay. The optimization model also considers minimizing the SA-TCP scheme
deployment cost by balancing the number of SA-TCP aggregators and the link
bandwidth, while still satisfying performance requirements
Design, Implementation, and Evaluation of Join and Split Strategy for Transmission control protocol running on Software Defined Networks
Software Defined Networks (SDN)-enabled switches of today can be empowered to
intelligently forward as well as elastically steer the network traffic. In this work, we focus
on developing a SDN-based framework to provide improved delivery performance
(of applications) in the network.
This dissertation proposed a new TCP join and split proxy on SDN platform. The
proposed framework allowed part of TCP (Transmission Control Protocol) optimization
to migrate from the application server to the proxy. Therefore, with a control
plane built between SDN controller and proxy, the SDN controller can further improve
the TCP delivery performance. The proxy (join-proxy) joins all TCP flows at the
beginning of the shared path into one long TCP flow. At the end of the shared path,
the proxy (split-proxy) splits the long flow for each joined client with the same TCP
session state. With the help of centralized controller of SDN and customized SDN
switch, the new design simplifies the TCP session synchronization between proxies.
Also, this dissertation developed Linked-ACK ((Acknowledgement) to maintain the
end-to-end semantic and limit the buffer size in each proxy by coupling the ACK of
three TCP flows separated by the join and split proxy. At the last, this dissertation
shows that the proposed proxy can well integrate with wireless network and MPTCP
(Multi-Path TCP) proxy [1]
The extensions of the proposed TCP Join and Split platform are applied to Smart
Grid network for improving fairness, WiFi network for reducing gaming traffic delay,
and Data Center network for addressing Virtual Machine (VM) live migration
problem.
First, the proposed TCP Join and Split platform can be applied to Smart Grid
network to provide better fairness on the application layer. The latest research in
Smart Grid communications has advocated the aggregation of multiple traffic flows
in order to achieve an improved throughput. While aggregation improves the overall
throughput, the individual flows still suffer from unfair throughput performance. As
a result, the enablers for time sensitive Smart Grid services, such as load-shedding
which requires a timely report of data, are mostly affected.
This dissertation proposed a novel SDN-based framework to provide fairness among
smart-meters (SMs) through flow aggregation and scheduling. By exploring the SDN’s
flow-level manageability features, for the first time in this paper, we present an
implementation-based architecture to perform effective aggregation-and-scheduling
of traffic flows. The proposed framework ensures fairness (among the smart-meters)
as well as improve the throughput performance. Our extensive experimental results
validate the efficacy of our proposed framework.
Second, the proposed TCP Join and Split platform can be applied to WiFi network
to reduce the gaming traffic delay. WiFi users typically expect different performance
requirements for various types of applications. For instance, users expect 'better and
consistent throughput' for Internet video consumption, and 'minimal delay' for local
network gaming applications. The wireless access substrate (at the consumer-end),
typically being the bottleneck in these networks, causes different users (in the same
WiFi coverage) to experience unfair and fluctuating network performance. To combat
such unfair situations, we need approaches to effectively control and steer the
applications’ traffic in the shared WiFi medium. However, a network that deals with
a crowd or private end-users (such as gaming multiplayers or the Internet content distributors),
encounters a major challenge in controlling the traffic without involvement
or modification at the end-host application devices.
In this dissertation, we propose a SDN-based seamless traffic steering and control
strategy in order to provide effective application-specific delivery services, such as
reduced delay (for gaming traffic) and improved throughput (for video consumption).
Unlike simulation-based solutions, our approach is production-ready, as we have implemented
our framework on a real network testbed environment. With extensive
performance study and sufficient mathematical insight, we demonstrate the prowess
of our proposed framework.
Last but not the least, the proposed TCP Join and Split platform can be applied
to Data Center network to optimize the VM live migration. With the growth of data
volumes and a variety of Internet applications, virtualization has become commonplace
in modern data centers and an effective solution to provide better management
flexibility, lower cost, scalability, better resources utilization, and energy efficiency.
One of the powerful features provided by virtualization is Virtual Machine (VM) live
migration, which facilitates moving workloads within the infrastructure with negligible
downtime and minimal impact on workload. However, the performance of running
applications is likely to be negatively affected during a live VM migration. The objective
of this paper is to optimize the total performance degradation of concurrent VM
live migration in the data center network by exploiting the SDN platform. The problem
is modeled using mixed integer linear programming(MILP) for VM live migration
with a fixed path and VM live migration with path selection. To provide a practical
optimization, the greedy algorithm is proposed. Numerical study results show that
a significant decrease occur in performance degradation in MILP model and greedy
algorithm when the number of VMs increases. The proposed greedy algorithm cannot
yield the optimum solution as the problem become harder, but it provides better
solution than MILP model in terms of the time constrain exhibited in case of large
problems
Heterogeneous wireless networks for smart grid distribution systems: Advantages and limitations
Supporting a conventional power grid with advanced communication capabilities is a cornerstone to transferring it to a smart grid. A reliable communication infrastructure with a high throughput can lay the foundation towards the ultimate objective of a fully automated power grid with self-healing capabilities. In order to realize this objective, the communication infrastructure of a power distribution network needs to be extended to cover all substations including medium/low voltage ones. This shall enable information exchange among substations for a variety of system automation purposes with a low latency that suits time critical applications. This paper proposes the integration of two heterogeneous wireless technologies (such as WiFi and cellular 3G/4G) to provide reliable and fast communication among primary and secondary distribution substations. This integration allows the transmission of different data packets (not packet replicas) over two radio interfaces, making these interfaces act like a one data pipe. Thus, the paper investigates the applicability and effectiveness of employing heterogeneous wireless networks (HWNs) in achieving the desired reliability and timeliness requirements of future smart grids. We study the performance of HWNs in a realistic scenario under different data transfer loads and packet loss ratios. Our findings reveal that HWNs can be a viable data transfer option for smart grids. 2018 by the authors. Licensee MDPI, Basel, Switzerland.Acknowledgments: This work was made possible by the United Arab Emirates University UPAR Grant No. 31N226.Scopu
Vulnerability Assessment and Privacy-preserving Computations in Smart Grid
Modern advances in sensor, computing, and communication technologies enable various smart grid applications which highlight the vulnerability that requires novel approaches to the field of cybersecurity. While substantial numbers of technologies have been adopted to protect cyber attacks in smart grid, there lacks a comprehensive review of the implementations, impacts, and solutions of cyber attacks specific to the smart grid.In this dissertation, we are motivated to evaluate the security requirements for the smart grid which include three main properties: confidentiality, integrity, and availability. First, we review the cyber-physical security of the synchrophasor network, which highlights all three aspects of security issues. Taking the synchrophasor network as an example, we give an overview of how to attack a smart grid network. We test three types of attacks and show the impact of each attack consisting of denial-of-service attack, sniffing attack, and false data injection attack.Next, we discuss how to protect against each attack. For protecting availability, we examine possible defense strategies for the associated vulnerabilities.For protecting data integrity, a small-scale prototype of secure synchrophasor network is presented with different cryptosystems. Besides, a deep learning based time-series anomaly detector is proposed to detect injected measurement. Our approach observes both data measurements and network traffic features to jointly learn system states and can detect attacks when state vector estimator fails.For protecting data confidentiality, we propose privacy-preserving algorithms for two important smart grid applications. 1) A distributed privacy-preserving quadratic optimization algorithm to solve Security Constrained Optimal Power Flow (SCOPF) problem. The SCOPF problem is decomposed into small subproblems using the Alternating Direction Method of Multipliers (ADMM) and gradient projection algorithms. 2) We use Paillier cryptosystem to secure the computation of the power system dynamic simulation. The IEEE 3-Machine 9-Bus System is used to implement and demonstrate the proposed scheme. The security and performance analysis of our implementations demonstrate that our algorithms can prevent chosen-ciphertext attacks at a reasonable cost
Current challenges and future trends in the field of communication architectures for microgrids
[EN] The concept of microgrid has emerged as a feasible answer to cope with the increasing number of distributed renewable energy sources which are being introduced into the electrical grid. The microgrid communication network should guarantee a complete and bidirectional connectivity among the microgrid resources, a high reliability and a feasible interoperability. This is in a contrast to the current electrical grid structure which is characterized by the lack of connectivity, being a centralized-unidirectional system. In this paper a review of the microgrids information and communication technologies (ICT) is shown. In addition, a guideline for the transition from the current communication systems to the future generation of microgrid communications is provided. This paper contains a systematic review of the most suitable communication network topologies, technologies and protocols for smart microgrids. It is concluded that a new generation of peer-to-peer communication systems is required towards a dynamic smart microgrid. Potential future research about communications of the next microgrid generation is also identified.This work is supported by the Spanish Ministry of Economy and Competitiveness (MINECO) and the European Regional Development Fund (ERDF) under Grant ENE2015-64087-C2-2. This work is supported by the Spanish Ministry of Economy and Competitiveness (MINECO) under grant BES-2013-064539.Marzal-Romeu, S.; Salas-Puente, RA.; González Medina, R.; Garcerá, G.; Figueres Amorós, E. (2018). Current challenges and future trends in the field of communication architectures for microgrids. Renewable and Sustainable Energy Reviews. 82(2):3610-3622. https://doi.org/10.1016/j.rser.2017.10.101S3610362282
The role of communication systems in smart grids: Architectures, technical solutions and research challenges
The purpose of this survey is to present a critical overview of smart grid concepts, with a special focus on the role that communication, networking and middleware technologies will have in the transformation of existing electric power systems into smart grids. First of all we elaborate on the key technological, economical and societal drivers for the development of smart grids. By adopting a data-centric perspective we present a conceptual model of communication systems for smart grids, and we identify functional components, technologies, network topologies and communication services that are needed to support smart grid communications. Then, we introduce the fundamental research challenges in this field including communication reliability and timeliness, QoS support, data management services, and autonomic behaviors. Finally, we discuss the main solutions proposed in the literature for each of them, and we identify possible future research directions
Smart Grid Communications: Overview of Research Challenges, Solutions, and Standardization Activities
Optimization of energy consumption in future intelligent energy networks (or
Smart Grids) will be based on grid-integrated near-real-time communications
between various grid elements in generation, transmission, distribution and
loads. This paper discusses some of the challenges and opportunities of
communications research in the areas of smart grid and smart metering. In
particular, we focus on some of the key communications challenges for realizing
interoperable and future-proof smart grid/metering networks, smart grid
security and privacy, and how some of the existing networking technologies can
be applied to energy management. Finally, we also discuss the coordinated
standardization efforts in Europe to harmonize communications standards and
protocols.Comment: To be published in IEEE Communications Surveys and Tutorial
Smart Metering Technology and Services
Global energy context has become more and more complex in the last decades; the raising prices of fuels together with economic crisis, new international environmental and energy policies that are forcing companies. Nowadays, as we approach the problem of global warming and climate changes, smart metering technology has an effective use and is crucial for reaching the 2020 energy efficiency and renewable energy targets as a future for smart grids. The environmental targets are modifying the shape of the electricity sectors in the next century. The smart technologies and demand side management are the key features of the future of the electricity sectors. The target challenges are coupling the innovative smart metering services with the smart meters technologies, and the consumers' behaviour should interact with new technologies and polices. The book looks for the future of the electricity demand and the challenges posed by climate changes by using the smart meters technologies and smart meters services. The book is written by leaders from academia and industry experts who are handling the smart meters technologies, infrastructure, protocols, economics, policies and regulations. It provides a promising aspect of the future of the electricity demand. This book is intended for academics and engineers who are working in universities, research institutes, utilities and industry sectors wishing to enhance their idea and get new information about the smart meters
Centralized Disturbance Detection in Smart Microgrids With Noisy and Intermittent Synchrophasor Data
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